In modern electronic systems, storage, retrieval, and recovery of digital information plays a significant role in the operation of devices included within such systems. A common example of an electronic system is a personal computer (PC), which requires access to digital data for processing thereof to perform and execute a wide variety of tasks. Digital data may be stored in a PC either internally as in a hard disk or externally in a mass storage data device such as a digital photo reader or a compact flash reader device.
In the conventional methods of accessing digital data, as implemented in electronic systems, an application program operating under a standard commercially available operating system accesses a mass storage data device for reading and/or writing of digital data. The operating system recognizes the mass storage data device and “mounts” it as an operating system data volume, i.e., a “disk drive”. The application program thereby accesses the mass storage data device at the logical level within the operating system using the operating system formatting information included within the mass storage data device.
However, the conventional methods of accessing digital data have a limitation that is encountered when the mass storage data device is for some reason corrupted. In the event of corruption of the mass storage data device, the electronic system cannot recover the digital data simply because the operating system is unable to communicate with the mass storage data device. Another limitation of the conventional methods of accessing digital data is that the application program commands the mass storage data device only with standard commands available to the operating system.
In light of the foregoing, it is desirable to develop a method and apparatus for accessing digital data even when the mass storage data device is corrupted and the operating system cannot communicate therewith. Further, the method and apparatus should not interfere with normal operations of the operating system, i.e. be transparent to the operating system. The desired method and apparatus should be able to access, retrieve, and recover information efficiently and cost-effectively.